The present application generally relates to systems and methods for providing feed-forward error correction in a driver circuit of a communication device.
Network service providers want to satisfy customer demand for high-speed data. One way to provide customers with high speed data is through the re-use of one or more existing metallic, e.g., copper, drop wires to the customer. However, in order to transmit increasingly higher speed data over metallic drop wires, the bandwidth and linearity of the driver circuit in the transmitting transceiver has to be correspondingly increased.
Unfortunately, however, the amplifier in the transmitting transceiver introduces significant distortion into the data signal making it difficult to achieve high linearity, particularly for greater bandwidths. Attempts have been made to compensate for the distortion introduced by the amplifier by using a feedback circuit to apply negative feedback. However, negative feedback creates trade-offs between linearity and bandwidth and between linearity and gain. That is, when negative feedback is used to compensate for amplifier distortion, linearity limits the extent to which bandwidth and gain can be increased.
To address some of the limitations of using negative feedback to compensate for distortion, a feed-forward error correction circuit can be used. However, there are challenges to using a feed-forward error correction circuit to compensate for amplifier distortion. Specifically, conventional circuits that combine correction outputs with the main outputs reduce the gain of the main path. Further, conventional feed-forward error correction circuits typically source a significant amount of current in order to achieve high linearity, resulting in increased demand on both the main path and the correction path. In fact, many conventional feed-forward error correction circuits reduce the gain of the amplifier by up to about 50%. As a result, adoption of feed-forward error correction circuits to compensate for amplifier distortion has been limited.